Osteitis condensans ilii

 History: 48-year-old asymptomatic G3P3 female.

Radiograph showing Bilateral, symmetric sclerosis of ilium along sacroiliac joint.

Axial CT of the pelvis showing sclerosis: arising along the iliac articular surface, extending laterally into adjacent marrow.

Coronal CT of the pelvis showing sclerosis: involving the iliac articular surface with no subchondral cysts, erosions, joint space narrowing

Etiology:

Response to mechanical stress from gravid uterus.

Prevalence:

Asymptomatic

F > M; 20-60 years old. Mean age 30

Characteristic imaging features:

Bilateral

Sclerosis: arises at the iliac articular surface, extending laterally

Triangular appearance; apex pointing cephalad

No evidence of other degenerative changes such as, subchondral cysts, erosions, joint space narrowing

References:

1. Parperis K, Psarelis S, Nikiphorou E. Osteitis condensans ilii: current knowledge and diagnostic approach. Rheumatol Int. 2020 Jul;40(7):1013-1019. doi: 10.1007/s00296-020-04582-9. Epub 2020 Apr 23. PMID: 32328707.
2. Williams PM, Byerly DW. Osteitis Condensans Ilii. 2022 Jun 5. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan–. PMID: 31855396.
3. Borlandelli E, Ciaffi J, Festuccia G, Facchini G, Miceli M, Brusi V, Mancarella L, Lisi L, Di Martino A, Faldini C, Meliconi R, Ursini F. Osteitis condensans ilii: prevalence and characteristics of a neglected mimic of sacroiliitis. Clin Rheumatol. 2022 Feb;41(2):483-490. doi: 10.1007/s10067-021-05925-y. Epub 2021 Sep 27. PMID: 34568992.